2004 Ford Super Duty 4x4 5.4 with 3.73 gears pulling a travel trailer that will be around 7000#s loaded. If I run the overdrive will it be destroyed?
Also MPG was 10.0 traveling around 55mph but I kept the overdrive off.

 

If you can lock out O/D, I would. My 2010 with TS trans doesn't offer the ability to lock out O/D. If it did, I would when towing our 8500~ lb 5th wheel. Less force on the TC and puts the engine in it's power band.

 

I wouldn't turn off the overdrive. If the trans will stay in overdrive without frequent downshifts you'll burn less gas. The trans was designed to tow in overdrive, you won't hurt it unless it is shifting frequently.

 

I doubt that 5.4 will hold overdrive. If it does, you'll be lugging the **** out of it. My V10 would hold O/D when towing 9k on level highway @ 65, but would only get about 8 mpg. Same trip on the return netted me just over 11, same speed, O/D locked off, with another 1500 lbs added.

Yea it would do it, but it was lugging it. Gassers like to spin a lil more when loaded, and are more efficient that way too.

 

In my 2000 F250 2wd, 5.4 with 4.10 limited slip,I towed trailers in excess of 10,000 up to 20,000+ and I rarely turned off the overdrive, I would rarely use the tow/haul mode, the truck has over 242,000 miles on it and I never had any drivetrain issues with the truck.

Somoene told me the newer trucks tow/haul mode change the shift points and use the engine to help braking.

 

That's true. The older trucks, before 2003, do not HAVE a tow/haul mode at all.

 

My 2010 has no way to lock out O/D and it does use engine braking on the downhills almost too aggressively. It holds O/D on the flats with no headwind towing our 5th wheel 65mph but the slightest incline like an overpass will cause a downshift. Won't hurt a thing.

 

Unless transmission hunts, there is no reason to turn OD off.

Steve

 

I had a 99SD with the 5.4 and 4:10 gears. Seems the only time I would tow out of O/D is when I was hauling 16 to 25000 pounds of grain in the wagons. Your 04 though should have a tow/haul. You could run it in that though.

 

A 2004 5.4L has the 4R100 trans with OD cancel and no tow/haul mode.

 

If it is like my 2012, you should be able to lock out any gear you want to, using the +/- on the shifter cloumn.

It was my understanding there were very few changes between to 2011 and 2012, but the engine and transmission as well as the running gear is the same.

In my 2000 F250 I rarely turned off the overdrive and I towed a lot of weight, I am in Florida so it is pretty flat, we do have the ocassional hill though.

 

I have the same truck only with a 6.8 v-10, I have never turned off the overdrive. And I tow a construction trailer frequently.

 

No +/- button on my 2010. It would be nice.

 

Usually critical in fuel saving while towing is having converter lock engaged.
When you pull on OD with convertor slipping -lot of engine energy goes into mixing the fluid, while turning OF off might get you converter lock on lower gear and fuel savings.
I don't know if your transmission has converter lock on lower gear, so that would be the first thing to check.
There is no worry about extra engine stress while on OD >>> if the engine can drive it, it can take it.
Other thing is listening to the engine fan. The fan takes lot of energy and drops mpg quite drastically. Sometimes lowering the speed by couple of miles keeps the engine colder and prevents the fan from coming on.

 

Your 2010 truck with a Torqshift doesn't need to have an O/D lockout. Put the truck in T/H mode, put the transmission in drive and let the truck decide what gear it wants to use.